مدل‌سازی مود اول شکست در جدایش رویه کامپوزیتی از هسته فوم الاستومری به‌کار‌رفته در تیرهای ساندویچی

نوع مقاله : مقاله مکانیک

نویسندگان

استادیار، دانشکده مهندسی عمران، دانشگاه فنی‌و‌حرفه‌ای، تهران، ایران.

چکیده

جدایش رویه از هسته در تیرهای ساندویچی یکی از مودهای خرابی شایع بوده و تحقیقات زیادی برای بررسی تاثیر مودهای مختلف شکست در این نوع خرابی انجام شده است. در مقاله حاضر جدایش رویه کامپوزیتی از هسته فوم الاستومری در تیرهای ساندویچی با انجام آزمایش و مدل‌سازی المان‌محدود بررسی شد که در مورد این نوع هسته‌ها سابقه نداشته است. مطالعه آزمایشگاهی بر روی تیرهای DCB ساخته شده از یک نوع فوم الاستومری با جنس PE-EVA و رویه‌های کامپوزیتی با الیاف شیشه (E) انجام شده و مقدار بحرانی نرخ رهاسازی انرژی کرنشی در این نمونه‌ها اندازه گیری شد.
در ادامه، مدل‌سازی المان‌محدود از نمونه‌های آزمایشگاهی انجام شده و با توجه به پیچیده بودن پاسخ فوم هسته در تیرهای DCB، سه رفتار مختلف هیپرالاستیک شامل رفتارهای فشاری، کششی و برشی برای فوم هسته در مدل‌ها تعریف و نتایج بار-جابجایی ملاحظه شده برای مدل‌های مختلف با نتایج آزمایشگاهی مقایسه شد. از مزایای مدلسازی المان‌محدود، بدست آوردن نمودارهایی برای توزیع مولفه‌های مختلف تنش در هسته تیرهای DCB بود. نتایج عددی، مدل‌های کالیبره شده با پاسخ برشی فوم را دارای دقت بیشتر نشان داد و گرچه در مدل‌ها، اندازه مقدار ماکزیمم تنش برشی نسبت به تنش نرمال حدود 25% بود، اما شبیه‌سازی رفتار فوم هسته بر اساس پاسخ برشی فوم توانست دقیق‌ترین نتایج را برآورد کند که نشانگر رفتار غالب در تیرهای DCB با هسته الاستومری بود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Simulation of fracture in first mode through debonding of composite skin from elastomeric foam core in sandwich beams

نویسندگان [English]

  • Alireza Nazari
  • Amir Hossein Karimi
Assistant Professor, Department of Civil Engineering, Technical and Vocational University, Tehran, Iran
چکیده [English]

Debonding of skin from core in sandwich beams has been concerned in many studies. In the present paper, the influence of first mode of fracture for debonding of composite skins from elastomeric foam core in sandwich beams was investigated through sufficient experiments and FE simulations. According to the results of experiments on DCB specimens, made by PE-EVA foam and composite E-glass skins, the critical value for strain energy release rate related to the first mode of fracture was measured.
The experimental specimens were simulated by FE models, considering hyperelastic response for elastomeric foam of the core, calibrated by compression, tension and shear tests on the foam and the load-displacement curves were compared for experiments and FE models. Using the FE models distribution of various components of stress along the foam core for the sandwich beams, with different responses of foam. The FE results related to assumption of shear response for foam were the most accurate numerical results compared to other models with tensile and compressive responses of the foam. Although the maximum value of the shear stress in the most accurate model was equal to 25% of the maximum normal stress to the beam longitudinal direction, simulation of debonding in sandwich beam based on shear response of foam core could achieve the most accurate results.

کلیدواژه‌ها [English]

  • Debonding
  • Sandwich beam
  • Composite skin
  • Elastomeric foam
  • Hyperelastic response
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